Melt butter and brown sugar in a small pan. Heat, stirring often, until mixture begins to bubble.
Add the heavy cream, 1 tablespoon at a time, and whisk well after each. The mixture may bubble up a little with the first tablespoon of cream. Turn off the heat. At this point it should look like a smooth caramel sauce.
Stir in the salt and remove from the stove.
Place the white chocolate chips in a heat-proof bowl and pour the hot caramel sauce over them. Stir until completely combined.
Divide the white chocolate caramel between the 6 glass dishes. Set aside.
Place both types of chocolate into a microwave safe bowl and heat in 15 second intervals, stirring in between each interval, until the chocolate is melted and well combined. Do not overheat it. Set aside to cool to room temp (but not cold).
Whip the chilled cup of cream and vanilla extract on high speed with a mixer, until soft peaks have formed. At that point, remove 3 tablespoons and set aside for use as a garnish.
Continue whipping the cream until stiff peaks form. This won’t take long so watch closely.
Pour the room temperature, melted chocolate into the cream and gently, but quickly, fold in the chocolate until it’s evenly combined.
Pipe (or dollop) the chocolate cream on top of the white chocolate caramel in your glass dishes.
Top each with a little bit of the soft whipped cream and garnish with chocolate shavings or chocolate sprinkles. Serve immediately.